Moving stairway handrail drive



Aug. 13, 1940. s. e. MARGLES MOVING STAIRWAY HANDRAIL DRIVE Filed Feb.11, 1939 2 Sheets-Sheet l SM cm MMZAI INVENTOR BY I "10mm ATTORNEY Aug.13, 1940. s. MARGLES 2,211,427

MOVING sTAIRw'AY HANDRAIL DRIVE Fild Feb. 11, 19:59 I 2 Sheets-Sheet 2 jFIGS 5M Cm MM LL INVENTOR BY ATTORNEY Patented Aug. 13, 1940 UNITEDSTATES MOVING STAIB-WAY HANDRAIL DRIVE Samuel Gustave Margles, Brooklyn,N. Y., as-

signor to Otis Elevator Company, New York, N. Y., a corporation of NewJersey Application February 11, 1939, Serial No. 255,823

1 Claim. (01. 198-16) The invention relates to handrails of movingstairways and especially to the driving of the handrails.

Moving Stairways are provided with moving handrails for the convenienceof persons using the stairways. Two handrails are provided, one

on each side of the stairs, and are arranged to be driven in synchronismwith the steps. It has been the practice for a great many years toprovide a traction drive for the handrails. In these arrangements, thehandrail passes around newel wheels at the ends of the stairway. At oneend of the stairway, the handrail passes from the newel wheel aroundtensioning wheels before returning to the incline, this newel wheel andat least one of the tensioning wheels being driven to drive thehandrail. On both the upper run and the return run of the incline, thehandrails slide on guides extending inside the handrail. With suchdrives, it is possible for the handrails to slip with respect to theirdriving sheaves. This results in relative motion between the handrailsand the steps, which is undesirable.

It is the object of the invention to provide a drive for the handrailswhich maintains the handrails in synchronism with the steps at alltimes.

The invention involves the provision of a positive drive for thehandrails with the handrails guided between the ends of the stairway bythe handrails themselves. In carrying out the invention, a sprocketchain is-secured to each handrail on the inner side thereof andthroughout the length of the handrail. The chain, and thus the handrail,passes over a sprocket wheel at each end of the stairway, one of thesesprocket wheels being driven to drive the handrail in synchronism withthe steps. The handrail extends directly from its run to the sprocketWheel and returns to its run directly from the sprocket wheel. The innersurface of the handrail is of material having a low coefiicient offriction to cooperate with the guides to guide the handrail between theends of the stairway with a minimum of friction. The chain extends alongthe longitudinal center of the handrail and is secured to the handrailby lugs formed at intervals on the chain links and extending into slotsin the handrail. The chain is positioned so that its pitch linecorresponds with a longitudinal line through the center of bending ofthe handrail so that the radii of bending of the chain and handrailcoincide at the curves.

Features and advantages of the invention will become apparent from thefollowing description and appended claim. In the drawings:

Figure 1 is a diagrammatic representation in side elevation of a movingstairway embodying the invention;

Figure 2 is an enlarged detail in crosssection of the handrail of Figure1;

Figure 3 is a fragniental top view of the handrail;

' Figure 4 is a fragmental view of the handrail in longitudinalcross-section;

Figure 5 is a view along the line 55 of Figure 4; and

Figure 6 is a schematic view of a broken-handrailswitch.

Referring to Figure 1, the moving stairway extends between alowerlanding l and an upper landing II. In the arrangement illustrated, thestairway comprises, endless series of steps l2 driven at the upper endof the stairway by means of sprocket wheels through running gear chains.These sprocket wheels are mounted on and driven by the main drive shaftl3 of the stairway. This drive shaft in turn is driven by an electricmotor I4 through reduction gearing l5, sprocket wheel [6, driving chainI1, and sprocket wheel l8 secured to shaft l3.

The stairway has two endless moving handrails, one on each side thereof,the handrail 20 for one side thereof being illustrated. This handrail isdriven from the main drive shaft l3 through sprocket wheel 2| secured tothe main drive shaft, sprocket chain 22, and sprocket wheel 23 oncounter shaft 24. A second sprocket wheel 25 on shaft 24 drives asprocket wheel 26 on the handrail drive shaft 21 by a sprocket chain 28.Driving sprocket 30 for the handrail is secured to the drive shaft 21.The handrail on the other side of the stairway is driven in a similarmanner from a sprocket wheel on shaft 24. Each of the handrails passesaround a similar sprocket wheel 3| at the lower end of the stairway. 0nthe upper run of the stairway each handrail is guided between its endsby guide 32. Also, a portion of the lower run of the handrail is guidedby guide 33. At the lower sprocket wheel 3| a guide shoe 34 is providedto lead the return run of the handrail onto or off the lower sprocketwheel. This guide shoe is bifurcated to straddle the driving chain. Theguide shoe is adjustably mounted for vertical movement by bolts 35extending into slots 36 in a feed bracket 31 and serves as a tensioningdevice to take up any slack in the handrail. 1

Referring now to Figures 2, 3, 4 and 5, the handrail is C-shaped incross-section and is of rubber reinforced with canvas. The inner surfaceof the handrail is covered with one or more layers of canvas tofacilitate sliding of the handrail on its guides 32 and 33. The handrailis provided throughout its length with a pocket 38 in its inner surfaceto receive the driving chain 40. This chain is of sprocket chainconstruction. The pocket 38 is of such depth that with the chain inplace the pitch line of the chain coincides with a line extendinglongitudinally of the handrail through the center of bending of thehandrail. The chain is secured to the handrail by means of lugs 4| whichextend sidewise oppositely from the outer edges of corresponding linksof the chain into slots 42 extending sidewise into the handrail from thepocket 38. The chain is held in position longitudinally of the handrailby rubber fillers 43 in the slots between the lugs. These fillers areformed by putting liquid rubber compound in the slots during assembly.This liquid rubber compound does not adhere to the lugs but does bind tothe handrail to form, when hardened, longitudinally yieldable retainersfor the lugs. Both the handrail and its driving chain are joined attheir ends to form a closed loop.

The guide 32 for the upper run of the stairway is illustrated in Figure2. This guide, which is preferably of brass, extends from the lower endto the upper end of the stairway and is secured at intervals to thestairway balustrading 44 by means of bolts 45. The guide is formed witha center pocket 46 to provide operating clearance for the chain and withflat portions 41, one on each side of the pocket, at the top forslidably supporting the handrail. The guide is also formed with V-shapedportions 48 which extend downwardly from the flat portions 41. The tips50 of the formation of the handrail are turned upwardly as viewed inFigure 2 so as to hook in behind the V portions of the guide to preventthe handrail being forced off its guide, the top of the handrail beingcrowned slightly to provide the desired stiffness. Considerable runningclearance is allowed between the handrail and the V portions 48 of theguide to enable the handrail to run freely on its guide.

The guide 33 for the lower run of the stairway is of a similarconstruction but is inverted. During this portion of the run thehandrail slides on the V-shaped portion 48 of the guide. At the lowerend of guide 33 the handrail is guided in such way that it may be ledoff at different angles to accommodate the position of guide shoe 34.This is preferably effected by a separate rounded guiding member 39 atthe lower end of guide 33.

A broken-handrail switch may be provided for each handrail if desired.Such switch may be of the form schematically illustrated in Figure 6,wherein a switch lever 52 pivotally mounted on shoe 34 is biased intoposition where the movable contact carried thereby engages a stationarycontact. This lever is adapted to be operated to separate the contactsby a. second lever 53, also pivotally mounted on shoe 34. This secondlever, is provided with a roller which rolls on the handrail and thussupports the lever in position disengaging the contact lever. Shouldbreaking of the handrail occur the roller drops, swinging the lever 53counterclockwise to open the switch. The contacts of the switch arearranged in the circuits so as to cause the stopping of the movingstairway in case the handrail breaks.

With handrails arranged as above described, the guiding of the handrailis effected by the handrail itself, independently of the driving chain,avoiding the use of any lubricant for the chain other than for the chainjoints. This is only a small amount of lubricant, that applied to thechain by the chain manufacturer being suiiicient for several yearsservice, so that the possibility of any oil getting on the handrail isminimized. Positive drive of the handrail assures correct speed of thehandrail, independent of rise, load or direction of travel. Tensilestresses in the handrail are minimized, eliminating resplicing of thehandrail and prolonging its life. The driving mechanism for the handrailis simplified, permitting a decrease in the width of the balustrading.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

A moving stairway comprising; a series of steps; a pair of handrails,one on each side of the steps, each handrail being c-shaped incrosssection and of rubber reinforced with canvas; a sprocket chain foreach handrail arranged on the inside of the handrail and extendinglongitudinally of the handrail for the full length thereof, each chainand the handrail for which it is provided being joined at theirrespective ends to form a closed loop, each handrail being provided witha pocket in its inner surface along the iongitudinal center of thehandrail to receive the sprocket chain, said pocket being of a depthsuch that the pitch line of the chain coincides with a line extendinglongitudinally of the handrail through the center of bending of thehandrail; lugs on each of said chains extending oppositely at intervalssidewise from the links of the chain, said handrails having slotsextending sidewise from said pockets to receive said lugs; fillersformed by providing liquid rubber compound in said slots during assemblyfor yieldably securing said chains to said handrails; guides for saidhandrails on the upper and lower runs of the stairway, said handrailshaving canvas linings on their inner surfaces for cooperating with saidguides to guide the handrails between the ends of the stairwayindependent of said chains, said linings extending over the surfaces ofsaid pockets and slots; sprocket wheels at the ends of the stairwayaround'which said chains extend; and motor driven mechanism acting onsaid sprocket wheels at one end of the stairway for driving saidhandrails in synchronism with said steps.

SAMUEL GUSTAVE MARGLES.

